1. Field of the Invention
The present invention relates to a metadata assignment method and a metadata assignment apparatus, and more particularly, to a technique that is adapted to be used for assignment of metadata, such as the name of a location and the name of an object, to a photograph.
2. Description of the Related Art
A method for assigning metadata, such as the name of a location and the name of an object, to a photograph for management of the photograph has started to be generalized. For example, photographs with metadata assigned thereto by users are published on a photograph sharing site on the web. If a user assigns metadata only to a small number of photographs, such as photographs to publish on the web, manual assignment of metadata is possible. However, for example, if a user tries to manually assign metadata to all of a large number of travel photos, this becomes a heavy burden to the user.
Under this circumstance, there has been proposed a method of utilizing metadata assigned to a similar image. For example, Japanese Patent Application Laid-Open No. 2002-024265 discusses a method of searching similar images on a photograph sharing site with use of a photograph to which a user wants to assign metadata as a query, extracting a plurality of metadata from photographs of the search result, and allowing the user to select which metadata is assigned to the target photograph.
Further, Japanese Patent Application Laid-Open No. 11-134344 discusses a method of searching similar images with use of a photograph which a user wants to assign metadata as a query, and assigning the same metadata as the metadata of the search result if the user determines that the image of the search result is actually similar to the target photograph.
The metadata assigned to photographs on, for example, a photograph sharing site, are basically assigned by users manually, and selected based on the users' subjective views. As such, it is inevitable that some photos are assigned metadata that fail to indicate the name of a location or the name of an object, and other photos are assigned metadata having poor representataiveness of the location or the object. Therefore, in conventional methods of assigning metadata based on similarity of an image, even if an image having extremely high similarity is found, assignment of appropriate metadata as the name of a location or the name of an object may not be able to be expected.
The same problem arises in a method of determining the location of a photograph based on the global positioning system (GPS) data, and utilizing metadata assigned to a photograph which was taken at a nearby place. In this case, the problem is that accurate determination of the location where the photograph was taken according to the GPS does not necessarily results in assignment of appropriate metadata.